Electromechanical dissociation (EMD) is defined as the inability of the heart to generate any cardiac output despite the presence of ECG complexes. Several authors have defined a subset of EMD termed pseudo- EMD. This has been defined as the presence of cardiac contractile function without palpable peripheral pulses. Some authors have suggested that patients in pseudo-EMD are more easily resuscitated than patients in true EMD. Currently, an inexpensive, portable, minimally invasive device to detect pseudo-EMD does not exist. Our preliminary studies using a Doppler flat flow probe taped to a esophageal tube demonstrated the consistent detection of pseudo-EMD. The purpose of this study is to construct a PETE-Doppler (Portable Emergency Trans Esophageal Doppler) device. We will assemble, test and evaluate this prototype on fully instrumental dogs, with respect to its accuracy in the detection of pseudo-EMD model. This canine model currently involves a short period of pseudo-EMD. Post-mortem examination of the esophagus will be performed to detect any traumatic damage caused by the device during cardiopulmonary resuscitation. The long term objective of this research is to provide an affordable, portable, minimally invasive instrument that will be useful in rapidly identifying patients in pseudo-EMD.